U.S. patent application number 11/019637 was filed with the patent office on 2006-06-29 for hearing protection earplug and use of the same.
This patent application is currently assigned to Phonak AG. Invention is credited to Roland Kurth.
Application Number | 20060137934 11/019637 |
Document ID | / |
Family ID | 36610092 |
Filed Date | 2006-06-29 |
United States Patent
Application |
20060137934 |
Kind Code |
A1 |
Kurth; Roland |
June 29, 2006 |
Hearing protection earplug and use of the same
Abstract
The invention relates to a hearing protection earplug comprising
a shell (10) to be worn at least in part in a user's ear canal,
said shell being adapted to provide for a mechanical acoustic
attenuation of at least 10 dB averaged over the audible frequency
range when worn by the user, an active unit (12) comprising an
acoustic output transducer (26) and means (30, 32, 60) for
producing output audio signals for said output transducer, and
means (34, 36, 38, 40, 56, 58, 80, 82, 84) for detachably
connecting said active unit to said shell, wherein said shell
comprises a sound passage (16, 16') extending between an outer
opening (14) of said shell and an inner sound output opening (18,
18') at the distal end of said shell and comprising valve means
(20, 120, 320) which are moveable, upon connecting said active unit
to said shell, from a closed position in which said valve means
acoustically close said sound passage into an open position in
which said valve means acoustically open said sound passage, said
valve means being biased towards said closed position in order to
acoustically close said sound passage when said active unit is
removed from said shell, and wherein said output transducer is
acoustically connected to said sound output opening via said sound
passage when said active unit is connected to said shell. The
invention also relates to the use of such a hearing protection
earplug.
Inventors: |
Kurth; Roland; (La
Neuveville, CH) |
Correspondence
Address: |
ROBERTS, MLOTKOWSKI & HOBBES
P. O. BOX 10064
MCLEAN
VA
22102-8064
US
|
Assignee: |
Phonak AG
Staefa
CH
|
Family ID: |
36610092 |
Appl. No.: |
11/019637 |
Filed: |
December 23, 2004 |
Current U.S.
Class: |
181/135 ;
181/130 |
Current CPC
Class: |
A61F 11/08 20130101;
B33Y 80/00 20141201 |
Class at
Publication: |
181/135 ;
181/130 |
International
Class: |
H04R 25/02 20060101
H04R025/02; A61B 7/02 20060101 A61B007/02 |
Claims
1. A hearing protection earplug comprising a shell to be worn at
least in part in a user's ear canal, said shell being adapted to
provide for a mechanical acoustic attenuation of at least 10 dB
averaged over an audible frequency range when worn by said user, an
active unit comprising an acoustic output transducer and means for
producing output audio signals for said output transducer, and
means for detachably connecting said active unit to said shell,
wherein said shell comprises a sound passage extending between an
outer opening of said shell and an inner sound output opening at a
distal end of said shell and comprising valve means which are
moveable, upon connecting said active unit to said shell, from a
closed position in which said valve means acoustically close said
sound passage into an open position in which said valve means
acoustically open said sound passage, said valve means being biased
towards said closed position in order to acoustically close said
sound passage when said active unit is removed from said shell, and
wherein said output transducer is acoustically connected to said
sound output opening via said sound passage when said active unit
is connected to said shell.
2. A hearing protection earplug comprising a shell to be worn at
least in part in a user's ear canal, said shell being adapted to
provide for a mechanical acoustic attenuation of at least 10 dB
averaged over the audible frequency range when worn by said user,
an active unit comprising a microphone, and means for detachably
connecting said active unit to said shell, wherein said shell
comprises a sound passage extending between an outer opening of
said shell and an inner sound output opening atdistal end of said
shell and comprising valve means which are moveable, upon
connecting said active unit to said shell, from a closed position
in which said valve means acoustically close said sound passage
into an open position in which said valve means acoustically opens
said sound passage, said valve means being biased towards said
closed position in order to acoustically close said sound passage
when said active unit is removed from said shell, and wherein said
microphone is acoustically connected to said sound output opening
via said sound passage when said active unit is connected to said
shell.
3. The earplug of of claim 1, wherein said connecting means
comprise sealing means for sealing the outer end of said sound
passage regarding the environment around said user by engagement
with said active unit.
4. The earplug of claim 1, wherein said connecting means are
adapted for clipping, screwing or bayonet coupling said active unit
to said shell.
5. The earplug of claim 1, wherein said connecting means are
adapted for clipping said active unit to said shell and wherein one
of said active unit and said shell comprises an element selected
from the group consisting of a radially movable element and a
resilient element, said element being adapted to engage a mating
element provided at the other one of said active unit and said
shell.
6. The earplug of claim 5, wherein said element is a radially
movable element and is biased radially towards a center of said
shell.
7. The earplug of claim 1, wherein said shell comprises an outer
cavity into which said active unit (12) is to be inserted.
8. The earplug of claim 1, wherein said valve means are adapted to
provide in said closed position for an acoustic attenuation of at
least 10 dB averaged over an audible frequency range.
9. The earplug of claim 1, wherein said valve means comprise a lid
which is adapted to be tilted, upon connecting said active unit to
said shell, from said closed position in which said lid extends
over the entire cross section of said sound passage into said open
position in which said lid exposes said sound passage.
10. The earplug of claim 1, wherein said active unit comprises a
projection for moving said valve means, upon connecting said active
unit to said shell, from said closed position to said open
position.
11. The earplug of claim 10, wherein said valve means comprise a
valve member which is axially movable within said sound passage by
said projection between a first axial position in which said valve
member acoustically closes said sound passage and a second axial
position in which said valve member acoustically opens said sound
passage.
12. The earplug of claim 11, wherein said valve member is biased
towards said first axial position by a spring element arranged at
least in part within said sound passage.
13. The earplug of claim 12, wherein said spring element is
arranged distal from said valve member.
14. The earplug of claim 11, wherein said valve member is adapted
to rest in said first axial position against a surface of said
sound passage for acoustically closing said sound passage.
15. The earplug of claim 11, wherein said valve member is selected
from the group consisting of a ball (120) and a plate.
16. The earplug of claim 11, wherein said sound passage comprises a
portion which is angled regarding the axial direction of said shell
and which is located distal from said first position of said valve
member.
17. The earplug of claim 1, wherein said means for producing audio
output signals comprises a microphone for converting ambient sound
into input audio signals and an audio signal processing unit for
processing said input audio signals into said output audio
signals.
18. The earplug of claim 17, wherein said means for producing audio
output signals comprise an interface for wireless connection with a
remote audio signal source such as a remote microphone.
19. The earplug of claim 18, wherein said interface is selected
from the group consisting of a radio frequency interface, an
inductive interface and an infrared interface.
20. The earplug of claim 19, wherein said interface is a Bluetooth
interface.
21. The earplug of claim 17, wherein said active unit comprises
dosimeter means for determining, by said microphone, a sound
exposure of said user.
22. The earplug of claim 21, wherein said dosimeter means are
adapted for comparing said determined sound exposure to regulations
implemented in said dosimeter means in order to judge whether said
sound exposure complies with said regulations.
23. The earplug of claim 1, wherein said shell has an outer surface
individually shaped according to the measured inner shape of the
user's outer ear and ear canal.
24. The earplug of claim 23, wherein said shell has an elasticity
of from shore D-85 to shore D-65.
25. The earplug of claim 24, wherein said shell is made of
polyamide.
26. The earplug of claim 19, wherein said interface is a frequency
modulated radio signal interface.
27. A use of a hearing protection earplug according to claim 1,
comprising: connecting said active unit to said shell by engaging
said connecting means, inserting said earplug at least in part into
said user's ear canal, removing said earplug from said user's ear
canal, disconnecting said active unit from said shell by
disengaging said connecting means, and inserting said earplug at
least in part into said user's ear canal.
28. The use of claim 27, further comprising: removing said earplug
from said user's ear canal, connecting a further active unit which
is functionally different from said active unit to said shell by
engaging said connecting means, and inserting said earplug at least
in part into said user's ear canal.
29. A hearing protection system comprising a shell to be worn at
least in part in a user's ear canal, said shell being adapted to
provide for a mechanical acoustic attenuation of at least 10 dB
averaged over an audible frequency range when worn by said user, a
plurality of functionally different active units comprising an
acoustic output transducer and means for producing output audio
signals for said output transducer, and means for detachably
connecting a selected one of said active units to said shell,
wherein said shell comprises a sound passage extending between an
outer opening of said shell and an inner sound output opening at a
distal end of said shell and comprising valve means which are
moveable, upon connecting said selected one of said active units to
said shell, from a closed position in which said valve means
acoustically close said sound passage into an open position in
which said valve means acoustically open said sound passage, said
valve means being biased towards said closed position in order to
acoustically close said sound passage when said selected one of
said active units is removed from said shell, and wherein said
output transducer is acoustically connected to said sound output
opening via said sound passage when said selected one of said
active units is connected to said shell.
30. A hearing protection system comprising a shell to be worn at
least in part in a user's ear canal, said shell being adapted to
provide for a mechanical acoustic attenuation of at least 10 dB
averaged over an audible frequency range when worn by said user, a
plurality of functionally different active units comprising a
microphone, and means for detachably connecting a selected one of
said active units to said shell, wherein said shell comprises a
sound passage extending between an outer opening of said shell and
an inner sound output opening at a distal end of said shell and
comprising valve means which are moveable, upon connecting said
selected one of said active units to said shell, from a closed
position in which said valve means acoustically close said sound
passage into an open position in which said valve means
acoustically open said sound passage, said valve means being biased
towards said closed position in order to acoustically close said
sound passage when said selected one of said active units is
removed from said shell, and wherein said microphone is
acoustically connected to said sound output opening via said sound
passage when said selected one of said active units is connected to
said shell.
31. Method for manufacturing a hearing protection earplug
comprising: providing a shell to be worn at least in part in a
user's ear canal, said shell being adapted to provide for a
mechanical acoustic attenuation of at least 10 dB averaged over an
audible frequency range when worn by said user, and said shell
comprising a sound passage extending between an outer opening of
said shell and an inner sound output opening at a distal end of
said shell; and providing an active unit comprising an acoustic
output transducer and means for producing output audio signals for
said output transducer, said active unit being adapted for being
detachably connected to said shell; said shell comprising valve
means which are moveable, upon connecting said active unit to said
shell, from a closed position in which said valve means
acoustically close said sound passage into an open position in
which said valve means acoustically open said sound passage, said
valve means being biased towards said closed position in order to
acoustically close said sound passage when said active unit is
removed from said shell, and said output transducer being
acoustically connected to said sound output opening via said sound
passage when said active unit is connected to said shell; wherein
said shell including said valve means is manufactured by an
additive layer-by-layer build-up process.
32. Method for manufacturing a hearing protection earplug
comprising: providing a shell to be worn at least in part in a
user's ear canal, said shell being adapted to provide for a
mechanical acoustic attenuation of at least 10 dB averaged over an
audible frequency range when worn by said user, and said shell
comprising a sound passage extending between an outer opening of
said shell and an inner sound output opening at a distal end of
said shell; and providing an active unit comprising a microphone,
said active unit being adapted for being detachably connected to
said shell; said shell comprising valve means which are moveable,
upon connecting said active unit to said shell, from a closed
position in which said valve means acoustically close said sound
passage into an open position in which said valve means
acoustically open said sound passage, said valve means being biased
towards said closed position in order to acoustically close said
sound passage when said active unit is removed from said shell, and
said microphone being acoustically connected to said sound output
opening via said sound passage when said active unit is connected
to said shell; wherein said shell including said valve means is
manufactured by an additive layer-by-layer build-up process.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a hearing protection earplug
comprising a removable active unit, to a use of such an earplug and
to a method for manufacturing such an earplug. The invention
further relates to a hearing protection system comprising an
earplug and a plurality of removable active units.
[0003] 2. Description of Related Art
[0004] US 2003/0112990 A1 relates to a hearing protection earplug
comprising a customized shell with an outer shape adapted to the
inner shape of the user's outer ear and ear canal. The shell
comprises a sound passage extending through the earplug, with the
outer end of the sound passage being provided with a slit membrane
which closes the sound passage whenever engaged by a remote
instrument such as a microphone of a measurement device. The shell
further comprises a receptacle for an insert member which may be a
communication element, i.e. an active unit, comprising a microphone
and a speaker, and which may be releasably engaged within the
receptacle of the shell. The receptacle communicates with a second
sound passage extending through the earplug.
[0005] US 2002/0080979 A1 relates to a hearing protection earplug
comprising a soft shell, i.e. a shell made of a relatively
resilient material which is capable of adapting its outer shape to
the inner shape of the user's outer ear and ear canal, into which
soft shell an electronic module, i.e. an active unit, may be
inserted in a detachable manner for enabling exchange of the soft
shell. The electronic module comprises a microphone, a signal
processing unit and a speaker for providing for an active hearing
protection function.
[0006] U.S. Pat. No. 5,631,965 relates to a hearing protection
earplug comprising a soft shell and an active unit which is screwed
into the shell. The active unit includes a microphone, a signal
processing unit and a speaker, with the speaker communicating with
a sound passage extending through the shell.
[0007] U.S. Pat. No. 6,687,377 B2 relates to a hearing protection
earplug comprising a shell with a sound measurement channel which
extends through the shell and which terminates at an opening at the
outer end of the shell. A remote device such as a sound measurement
device may be temporarily inserted into the outer opening of the
sound measurement passage.
[0008] US 2003/0037989 A1 relates to an earplug comprising a
customized shell which is provided with a receptacle into which a
hearing aid module comprising a microphone, a signal processing
unit and a speaker may be releasably inserted for allowing exchange
of the shell. The speaker of the hearing aid module communicates
with a sound passage extending through the shell.
[0009] It is an object of the invention to provide for a hearing
protection earplug which allows for a highly flexible use by
enabling the user to select between different functions in a simple
and easy manner. It is a further object of the invention to provide
for a manufacturing method and a use of such an earplug and for a
hearing protection system comprising such an earplug.
SUMMARY OF THE INVENTION
[0010] These objects are attained according to the present
invention by a hearing protection earplug as defined in claims 1
and 2, respectively, by a use of such a hearing protection earplug
as defined in claim 27, by a method for manufacturing such an
earplug as defined in claim 30 and by a hearing protection system
comprising such an earplug as defined in claim 29.
[0011] The invention is beneficial in that the hearing protection
earplug can be used, according to the desires of the user, either
without the active unit being inserted into the shell, with the
hearing protection earplug in this case acting as a passive hearing
protection earplug with the sound passage being closed by the valve
means, or with the active unit being inserted into the shell, with
the hearing protection earplug in this case being provided with
additional functionality, such as a selective communication
function, i.e. the earplug acting as an active hearing protection
device, or an in-situ sound attenuation measurement function, with
the active unit being acoustically connected via the opened valve
means with the sound passage. The invention also allows for
alternatively using active units having different functionality
with the same earplug in order to provide for a particularly high
flexibility of use. Due to the provision of the acoustic valve
means the change between different use modes and hence the handling
of the earplug by the user is particularly simple. Further, due to
the fact that the active unit can be easily removed from the shell,
the earplug is easy to clean. Finally, by manufacturing the shell
together with the valve means by an additive layer-by-layer
build-up process, the valve means can be implemented in a
particularly simple manner without the need of a separate assembly
step for mounting the valve means at the shell.
[0012] Preferred embodiments of the invention are defined in the
dependent claims.
[0013] These and further objects, features and advantages of the
present invention will become apparent from the following
description when taken in connection with the accompanying drawings
which, for purposes of illustration only, show several embodiments
in accordance with the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIGS. 1a and 1b show a schematic side view, partially in
cross-section, of the distal end of a first embodiment of a hearing
protection earplug according to the invention, wherein the active
unit is shown in a condition prior to being fixed within the shell
and after having been fixed within the shell, respectively; and
[0015] FIG. 2 to FIG. 4 show views, similar to that of FIG. 1a, of
modified embodiments of the invention.
[0016] The present invention relates to hearing protection earplugs
comprising a shell which is adapted to be worn at least in part in
a user's ear canal, i.e. at least a distal portion of the shell is
to be inserted into the outer part of the user's ear canal in order
to provide for an acoustic attenuation of at least 10 dB averaged
over the audible frequency range when the earplug is worn by the
user, in order to protect the user from excessive levels of ambient
sound. The earplug may comprise an acoustic filter for adjusting
the desired total acoustic attenuation or for adjusting the
frequency dependent acoustic attenuation.
[0017] The shell preferably is a hard shell having an elasticity
from shore D85 to D65 and preferably is made of polyamide. In order
to achieve optimized fit of the shell within the user's outer ear
and ear canal, the shell preferably has an outer surface
individually shaped according to the measured shape of the user's
outer ear and ear canal, i.e. the shell preferably has an
individually customized outer shape. The shape of the user's outer
ear and ear canal may be determined by direct three-dimensional
scanning of the ear canal and the concha or by producing an
impression of the ear canal and the concha which subsequently
undergoes scanning. The scanning process may be carried out
optically, preferably by laser scanning.
[0018] The digital data obtained by the scanning process is then
used to create the hard shell by an additive or incremental
layer-by-layer build up process. Such processes are also known as
"rapid prototyping". A preferred additive build-up process is a
layer-by-layer laser sintering process of powder material,
preferably polyamide powder. Such processes are also known as
"selective laser sintering" (SLS). The basic principle therein is
the repeated deposition of a thin layer of material on a surface,
with the desired sectional shape then being stabilized, i.e.
hardened, by laser action. An overview regarding such processes can
be found, for example, in US 2003/0133583 A1 or U.S. Pat. No.
6,533,062 B1.
[0019] According to the invention, the shell is provided with a
sound passage which extends between an outer opening of the shell
and an inner sound output opening at the distal end of the shell.
Further, the shell comprises valve means which are movable between
a closed position in which the valve means acoustically open the
sound passage, with the valve means being biased towards the closed
position. The shell further is adapted to be detachably connected
with an active unit which causes the valve means to move from the
closed position into the open position upon engagement between the
active unit and the shell. Thereby it is possible to use the
earplug as a passive hearing protection earplug with the active
unit being removed, or as a hearing protection earplug with added
functionality provided by the active unit when connected to the
shell.
[0020] Preferably, the valve means provides in the closed position
for an acoustic attenuation of at least 10 dB averaged over the
audible frequency range. In general, the overall acoustic
attenuation provided by the earplug should be at least 10 dB more
when the valve means are closed, compared to the case when the
valve means are open.
[0021] The active unit may comprise an acoustic output transducer
and means for producing audio signals for the output transducer,
with the output transducer being acoustically connected to the
sound output opening of the shell via the sound passage when the
active unit is connected to the shell. The means for producing
audio signals for the output transducer may comprise a microphone
included within the active unit for sensing ambient sound and/or an
interface for wireless connection with a remote audio signal
source, such as a remote microphone. In both cases the active unit
provides for an active hearing protection function to the earplug
by enabling communication, in particular speech communication, via
the microphone and the output transducer while the earplug is worn
by the user.
[0022] Alternatively or in addition, the active unit may comprise a
microphone which is adapted to be acoustically connected to the
sound output opening of the shell via the sound passage when the
active unit is connected to the shell. In this case, the microphone
may be used for in-situ attenuation measurements of the earplug
when worn by the user. In addition, the active unit may comprise
dosimeter means connected to the microphone for determining the
actual sound exposure experienced by the user's ear. The dosimeter
means may be adapted for comparing the determined actual sound
exposure to regulations implemented in the dosimeter means in order
to judge whether the sound exposure complies with the
regulations.
[0023] Usually the active unit comprises an audio signal processing
unit for processing input audio signals provided by the microphone
sensing ambient sound into the output audio signals for the output
transducer. If a remote microphone is provided, the interface for
wireless connection may be a radio frequency interface, in
particular a frequency modulated radio signal interface or a
Bluetooth interface, an inductive interface or an infrared
interface.
[0024] In general, the earplug may be designed such that the user
not only has the choice to use the earplug with or without the
active unit but in addition the user has the option to select
between functionally different active units, for example, one with
a microphone and an output transducer for providing for an active
hearing protection function, and one with a microphone and
dosimeter means for providing for a dosimeter and sound exposure
monitoring function. Thereby the flexibility of the hearing
protection system is further enhanced.
[0025] In general, it is possible and desirable to manufacture not
only the shell by a layer-by-layer build-up process, but also the
functional components integrated within the shell, such as the
valve means, whereby the manufacturing process can be significantly
simplified.
[0026] In the following, examples of the design of the means for
connecting the active unit to the shell and the valve means will be
illustrated by reference to the drawings.
[0027] In general, the connecting means may be adapted for
clipping, screwing or bayonet coupling the active unit to the
shell. However, also any other quickly detachable connection may be
used.
[0028] FIGS. 1a and 1b show an example where an active unit 12 is
connected to a shell 10 by a bayonet coupling mechanism. In all
Figures, only the distal portions of the shell 10 and the active
unit 12 are shown, with the distal end of the shell being located
at the bottom of each Figure. The shell 10 comprises an outer
cavity 14 forming an outer opening into which the active unit 12
can be inserted for being connected to the shell 10. The outer
cavity 14 is connected at its distal end to a sound passage 16
which extends between the outer cavity 14 and an inner sound output
opening 18 provided at the distal end of the shell 10.
[0029] Within the sound passage 16 a valve member 20 is provided
which is designed as a lid which is adapted to be tilted from a
closed position, in which the lid 20 extends over the entire
cross-section of the sound passage 16 (see FIG. 1a), into an open
position in which the lid 20 exposes the sound passage 20 (see FIG.
1b). The dashed lines in FIG. 1a indicate an intermediate position
of the lid 20. In the closed position, the lid 20 serves to
acoustically close the sound passage 16 regarding the outer cavity
14.
[0030] In addition to the sound passage 16 the shell 10 may
comprise a sound channel 22 extending from the outer cavity 14 to
the distal end of the shell 10 which is acoustically closed by a
passive filter element 24. The filter element 24 is provided for
achieving a defined frequency dependent acoustic attenuation by the
shell 10, whereby, for example, speech frequencies may be
attenuated less than high frequency noise.
[0031] The active unit 12 comprises an acoustic output transducer
26, i.e. a speaker, at its distal end, which distal end is formed
as an axial protection 28 adapted to move the lid 20 from the
closed position shown in FIG. 1a into the open position shown in
FIG. 1b, when the active unit 12 is connected to the shell 10. The
lid 20 is biased towards the closed position of FIG. 1a in order to
acoustically close the sound passage 16 when the active unit 12 is
removed from the shell 10. In the position of FIG. 1b, wherein the
active unit 12 is connected to the shell 10, the output transducer
26 is acoustically connected to the inner sound outlet opening 18
via the open sound passage 16.
[0032] The active unit 12 further comprises an audio signal
processing unit 30 which processes input audio signals received
from a microphone 32 into output audio signals for the output
transducer 26.
[0033] The shell 10 is provided with a sealing lip 34 adapted for
engagement with a mating groove 36 at the active unit 12 in order
to seal the outer end of the sound passage 16 regarding the outer
cavity 14 and hence regarding the environment around the user when
the active unit 12 is connected to the shell 10.
[0034] The active unit 12 further comprises radial projections 38
which are adapted for engagement with mating slots 40 provided at
the shell 10. The slots 40 and the radial projections 38 are
designed for providing for a bayonet-like engagement between the
active unit 12 and the shell 10 when the active unit 12 is inserted
into the shell 10 and is slightly rotated against the shell 10.
[0035] When the active unit 12 is removed from the shell 10 again
the lid 10 will automatically move into the closed position shown
in FIG. 1a due to the biasing forces.
[0036] In FIG. 2 a modified embodiment is shown in which the
bayonet mechanism of FIGS. 1a and 1b is replaced by a screw
mechanism and wherein the lid-like valve member 20 is replaced by a
ball-like valve member 120.
[0037] In general, FIG. 2 is an example of the case in which the
acoustic valve comprises a valve member which is axially movable
within the sound passage between the closed position and the open
position, with the valve member being biased towards the closed
position by a spring element which is arranged distal from the
valve member.
[0038] In the embodiment shown in FIG. 2, a spring element 50 rests
against the distal end of the shell 10 in order to bias the ball
120 outwardly against a spherically shaped surface 52 of the sound
passage 16 in order to acoustically close the sound passage 16 when
the active 12 is not connected to the shell 10. The spring element
50 is located within an inner cavity 54 of the shell. In the
embodiment of FIG. 2 the sound passage 16 comprises a portion 16'
which is angled regarding the axial direction of the shell 10 and
which is located distal from the closed position of the ball 120.
In the embodiment of FIG. 2 the angled portion 16' of the sound
passage 16 extends to an outer sound outlet opening 18' at the
distal end of the shell 10, with the angled portion 16' thus
bypassing the inner cavity 54 in which the spring element 50 is
located.
[0039] When the active unit 12 is inserted into the shell 10, the
axial protection 28 will axially move the ball 120 from the closed
position of FIG. 2 towards the distal end of the shell 10 against
the biasing force of the spring element 50, thereby reaching the
open position in which the centre of the ball 120 is located distal
from the point where the angled portion 16' starts, thereby
acoustically opening the sound passage 16, 16' extending from the
outer cavity 14 towards the inner sound outlet opening 18'.
[0040] In the embodiment of FIG. 2, the active unit 12 and the
shell 10 are provided with mating threads 56, 58 in order to allow
the active unit 12 to be screwed into the shell 10 for connecting
the active unit 12 to the shell 10. Preferably the thread is so
steep that rotation corresponding to from a half turn to a full
turn is sufficient for achieving engagement between the active unit
12 and the shell 10.
[0041] A further difference between the embodiment of FIGS. 1a and
1b and FIG. 2 is that in the embodiment of FIG. 2 the internal
microphone 32 of the active unit 12 is replaced by an interface 60
adapted for wireless communication with a remote audio signal
source 62. The remote audio signal source 62 preferably comprises a
microphone 64 in order to allow for wireless communication between
the person using the earplug comprising the shell 10 and the active
unit 12 and a second person using the external audio source 62 with
the external microphone 64. The interface 60 may be, for example, a
frequency modulated radio frequency interface or a Bluetooth
interface.
[0042] In the embodiment of FIG. 3 the ball 120 is replaced by a
valve plate 220 which is located in the closed position proximal
from the point where the angled portion 16' of the sound passage 16
starts, while the plate 220 is located in the open position
proximal from that point in order to open the sound passage 16, 16'
from the outer cavity 14 to the inner sound outlet opening 18'. In
the closed position the valve plate 220 is biased by the spring
element 50 against an axially oriented surface of the sound passage
16.
[0043] Further, the embodiment of FIG. 3 is an example for a
clipping or snap-in mechanism for connecting the active unit 12
with the shell 10. Such mechanism may be generally achieved by
providing either the active unit 12 or the shell 10 with a radially
movable or resilient element adapted to engage a mating element
provided at the counterpart, i.e. the shell 10 or the active unit
12, respectively.
[0044] More specifically, the embodiment of FIG. 3 is an example in
which the shell 10 is provided with a rigid radially projecting
projection 70, while the active unit 12 is provided with a soft lip
72 comprising a circumferential groove 74 into which the
projections 70 of the shell 10 will engage when the active unit is
axially pressed into the outer cavity 14 of the shell 10.
[0045] In the embodiment of FIG. 4 a modification of the
clipping/snap-in mechanism is shown wherein the resilient lip 72 is
replaced by a circumferential groove 80 provided at the outer
surface of the active 12 and wherein the rigid projections 70 of
the shell 10 are replaced by radially movable elements 82 which are
radially biased towards the centre of the shell 10 by spring
elements 84. In the example shown in FIG. 4 the engagement elements
84 are balls.
[0046] Further, in the embodiment of FIG. 4 the valve plate 220 is
replaced by a conical body 320 which is tapered towards its outer
end while its distal end fills the entire cross-section of the
sound passage 16. In the closed position shown in FIG. 4 the distal
end of the valve body 320 is located proximal from the point where
the angled portion 16' of the sound passage 16 starts, while in the
open position the valve body 320 is forced into the distal
direction by the axial projection 28 of the active unit 12 so far
that the distal end of the valve body 320 is located distal from
the point where the angled portion 16' of the sound passage 16
starts, so that an acoustic connection between the outer cavity 14
and the inner sound outlet opening 18' via the sound passage 16,
16' is opened.
[0047] In the embodiment of FIG. 4 the active unit is provided with
a distal microphone 86 which may be present alternatively or in
addition to an output transducer 26. The distal microphone 86 may
serve for performing in-situ sound attenuation measurements when
the shell 10 is worn within the user's ear canal. Alternatively or
in addition the distal microphone 86 may be connected to a digital
data processing unit 88 which may serve as a dosimeter for
determining and recording the actual sound exposure experienced by
the user when wearing the earplug. In addition, the unit 88 may
serve to compare the determined sound exposure to regulations
implemented in the unit 88 in order to judge whether the determined
sound exposure complies with the regulations, whereby a
corresponding alarm signal may be output, i.e. an alarm sound or
synthetic speech, if the regulations are infringed.
[0048] In FIG. 3 an example of an active unit 12 is shown which
includes only a distal microphone 86 and a digital data processing
unit 88 serving as a dosimeter.
[0049] While various embodiments in accordance with the present
invention have been shown and described, it is understood that the
invention is not limited thereto, and is susceptible to numerous
changes and modifications as known to those skilled in the art.
Therefore, this invention is not limited to the details shown and
described herein, and includes all such changes and modifications
as encompassed by the scope of the appended claims.
* * * * *